The hydrofracturing, or hydraulic fracturing, technology is the fracturing of rock by a pressurized liquid. It has become a preferred method for extracting and recovery of shale oil and gas, tight gas, tight oil, and coal seam gas. A high pressure liquid is filled in a wellbore and causes a terrain to fracture. A propping agent in the high pressure liquid allows a crack to be held open, and also serves as a quick penetration channel for oil-gas steering drilling.
The fracturing liquid used in the hydrofracturing method available for recovery of shale gas typically includes water, sand and chemical additives (e.g., salts and emulsifying agents). The fracturing liquid is typically made up of 99% or more water and sand. It usually requires a very large amount of fracturing liquid for the exploitation of shale gas. A typical shale gas wellbore may require about 4 to 5 million gallons (1 gallon corresponding to about 3.78 L) of the fracturing liquid.
Metal pipes are commonly used for long distance delivery (in the scale of about 10 miles) in recovery of shale oil and gas. Laying long distances of metal pipes is labor intensive and very difficult in complex terrains, such as slopes, ravines, and ponds. More importantly, couplings of metal pipes are susceptible to cracking and leaking, which poses a great risk of soil pollution caused by leaked fracturing liquid.
Flexible hoses that can withstand the rigors of commercial fracking operations are highly desirable.
The present invention provides flexible hoses that have high structural integrity, long service life and weather- and chemical-resistance, are resistant to flex-cracking and high pressure, can withstand high delivering rate of fracturing fluid, and are suitable for various terrain topographies. When not in service, it lays flat, and can be easily wound, taking up less space for storage and transportation.